CVE-2026-81578: papercut mf — Actively Exploited & Fix

Description

An improper access control vulnerability exists in the web management interface of PaperCut MF and PaperCut NG. Under specific conditions, unauthenticated remote requests targeting administrative functions can trigger backend actions prior to the completion of access validation checks. This allows an unauthenticated remote attacker to modify certain system configurations.

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CVSS v3.1 Score

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0448

Probability of exploitation

0.91%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

CISA Known Exploited Vulnerability

This vulnerability is actively exploited in the wild.

Added: Aug 31, 2026 Remediation due: Sep 14, 2026

Weakness Type (CWE)

CWE-305 CWE-305

Affected Products

Vendor	Product	Versions
papercut	papercut_mf	< 24.1.9
papercut	papercut_mf	25.0.2 — 25.0.12
papercut	papercut_mf	26.0.2 — 26.0.4
papercut	papercut_ng	< 24.1.9
papercut	papercut_ng	25.0.2 — 25.0.12
papercut	papercut_ng	26.0.2 — 26.0.4

References

Advisories & Patches

https://www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/ https://github.com/rapid7/metasploit-framework/pull/21842 https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-81578

Frequently Asked Questions

What is CVE-2026-81578? +

An improper access control vulnerability exists in the web management interface of PaperCut MF and PaperCut NG. Under specific conditions, unauthenticated remote requests targeting administrative functions can trigger backend actions prior to the completion of access validation checks. This allows an unauthenticated remote attacker to modify certain system configurations. It has a CVSS v3.1 base score of 9.8 (CRITICAL). This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.

How severe is CVE-2026-81578? +

CVE-2026-81578 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0448, placing it in the 1th percentile for exploitation probability.

What products are affected by CVE-2026-81578? +

CVE-2026-81578 affects products from papercut, specifically: papercut_mf, papercut_ng. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-81578? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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